Previous studies have show that when cats with localized Brugia malayi are secondarily infected with one of several microorganisms, lymphatic dysfunction resulting in edema and fibrosis more persistent and more extensive than following infection with B. malayi or with the microorganism alone. Long term observations will be made on cats infected with B. malayi and a feline strain of streptococci to determine if the elephantoid condition seen in a proportion of these animals will persist for a period of many months. The difference between the popliteal lymph node and afferent lymphatics in cats with persistent elephantiasis and those in which edema quickly subsides will be compared by lymphography and by direct observations at necropsy. Procedures for infecting cats with B. malayi and secondarily with a human strain of Sporothrix schenckii will be modified to determine if the chronicity of this combined infection can be enhanced. Patas monkeys will be infected with B. malayi by using procedures found to be effective for studying localized B. malayi infections in cats. Migration patterns, survival rates and the final location of adult B. malayi in the hind limb, as well as the resulting pathology of the regional lymphatics, will be recorded. B. malayi-infected cats, treated with diethylcarbamazine, will be injected intravenously with streptococci to determine if accumulations of dead worms will serve as a nidus for colonization of microorganisms during a transient bacteremia.